1. Technical Field
The present invention relates to lens units, and particularly to a camera module with the lens unit for use in a digital camera or a portable electronic apparatus such as a mobile telephone, a personal digital assistant, etc.
2. Description of Related Art
A lens unit, which is constructed by disposing an optical system such as a lens in a lens barrel, is included in various types of camera modules for use in a video camera, a still camera, a mobile phone, a personal digital assistant, a notebook computer, etc. An example of such a camera module is one that is equipped with a movable section having a movable lens for zooming or focusing, in which the movable section can be moved by a linear actuator in an optical axis direction of the lens. The movable section is supported by a pair of guide shafts, to be movable in the optical axis direction. The movable section is guided by the pair of guide shafts and moves in the optical axis direction by a drive of the linear actuator.
However, the above-mentioned camera module which has the guiding shafts for guiding the movable section has some technical issues: it requires a space for accommodating the guiding shafts; such a space deviates from a compact requirement for the camera module. Furthermore, it requires a clearance of several microns between the movable section and the guiding shafts for enabling the movable section to move smoothly on the guiding shafts. However, such a clearance may cause the movable section to have a lateral movement and/or an inclination with respect to the optical axis during the movement of the movable section on the guiding shafts. Such a lateral movement and inclination of the movable section may cause deterioration in quality of a captured image because an image focal point may deviate or a so-called image-shake phenomenon may be generated.
Accordingly, it is desirable to realize reduction of size in a lens unit including a movable section and/or an camera module having such a lens unit. Furthermore, it is desirable to improve reliability of operation of a movable section included in a lens unit and/or a camera module including such a lens unit. The present invention is conceived in view of the above-described technical issues.